Theory Manual Version 3.4
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Subsection 7.9.2: Joint Axes Up Section 7.9: Rigid Connectors Subsection 7.9.4: Joint Reaction Forces and Moments

### 7.9.3 Relative Joint Motion

The position of a joint in each rigid body is given in (7.9-1). The relative motion across a joint is given by the relative translation and the relative rotation where is the skew-symmetric tensor with dual vector . As usual, is a vector whose direction represents the axis of rotation and whose magnitude is the angle of (counter-clockwise) rotation about that axis. To report the relative motion of a joint, we may project and along the basis vectors of the first rigid body. Thus,
Subsection 7.9.2: Joint Axes Up Section 7.9: Rigid Connectors Subsection 7.9.4: Joint Reaction Forces and Moments